Recently, there is extensively used an endoscope (called a scope or fiber scope) whereby organs within a body cavity can be observed by inserting a fine diameter insertable part into the body cavity or, as required, various curing treatments can be made by using a treating tool inserted through a treating tool channel.
Also, an electronic scope wherein such solid state imaging device as a charge coupled device (CCD) is used is variously suggested. This electronic scope has such advantages that the resolution is higher than in a fiber scope, it is easy to record and reproduce picture images and such picture image treatments as the magnification of picture images and the comparison of two picture images are easy.
Among the systems of imaging color picture images of the above mentioned electronic scope, there are such frame sequential type wherein the illuminating light is sequentially switched to R (red), G (green) and B (blue) as is shown, for example, in the gazette of a Japanese patent application laid open No. 82731/1986 and such color mosaic type (called also a simultaneous type) wherein a filter array in which color filters transmitting respectively such color lights as of R, G and B are arranged in the form of a mosaic is provided on the front surface of a solid state imaging device as is shown, for example, in the gazette of a Japanese patent application laid open No. 76888/1985. The frame sequential type has an advantage that pixels can be made fewer than in the color mosaic type. On the other hand, the color mosaic type has an advantage that no color displacement is produced for a quickly moving object to be imaged.
There are many kinds of the above mentioned electronic scope depending on the using objects. For example, an insertable part of an outside diameter of about 10 mm is used for an upper or lower digestive organ. On the other hand, an insertable part of an outside diameter less than about 5 mm is usually required, for example, for bronchia. Thus, it is physically and functionally unreasoanble to use the same kind of imaging device and the same kind of imaging system for various electronic scopes in which the outside diameter of the insertable part varies in a wide range. That is to say, for example, in order to realize an electronic scope for bronchia (fine diameter), an imaging device of few pixels can not help being used.
Thus, in case the pixels are few, in order to prevent the reduction of the resolution, the frame sequential type color imaging system wherein an object is illuminated in a frame sequential system with lights of respective wavelengths of R, G and B and frame sequential images are made under this illumination and are combined to color-display the object image is more advantageous than the color masaic type imaging system wherein color mosaic filters are used.
On the other hand, it is advantageous for the improvement of the picture quality to make the imaging system a color mosaic type by increasing pixels for the outside diameter of about 10 mm.
Now, the above mentioned fiber scope or electronic scope is used generally as connected to a light source apparatus feeding illuminating lights adapted to the respective scopes.
The illuminating method is different among the above mentioned fiber scope, frame sequential type electronic scope and color mosaic type electronic scope. That is to say, a white color light is required for the fiber scope and color mosaic type electronic scope. A light which is sequentially switched to R, G and B is required for the frame sequential type electronic scope. Further, even in the same frame sequential type imaging system, the spectral intensity and blanking period of the illuminating light must be varied in response to the kind of the solid state imaging device and the use of the endoscope. Therefore, the user must prepare respectively different light source apparatus depending on the kinds of the scopes and must make different operations. Thus, the economy and efficiency have been low.
By the way, a system wherein a fiber scope provided with an optical fiber bundle for transmitting images is connected to a controlling apparatus for an electronic scope provided with a frame sequential type light source apparatus so that the image may be observed on such displaying picture surface as of a monitor television is disclosed in the gazette of a Japanese patent application laid open No. 243625/1985. However, with this system, no electronic scope of a color mosaic type can be used and no naked eye observation can be made by using a fiber scope.